1. Field of the Invention
The present invention relates to a side door for a vehicle which includes an airbag that inflates upward from the side door in response to, for example, a side collision of the vehicle, to thereby protect the head and other body parts of a vehicle occupant.
2. Description of the Related Art
Japanese Patent Application Laid-Open (kokai) No. H5-139238 discloses a conventional side door for a vehicle designed to cause an airbag to inflate upward from the side door in response to a side collision of the vehicle.
The publication does not specifically disclose a structure which enables a trim cover to be push-opened upon inflation of the airbag. However, in general, a thin portion which is readily bent and serves as a hinge portion is provided at the upper portion of the trim cover such that the hinge portion extends straight over a long distance in the fore-aft direction of the vehicle. In this case, upon receipt of inflation force of the airbag, the entire upper wall portion of the trim cover is push-opened such that the upper wall portion rotates as a single member about the straight hinge portion, and thus an opening through which the airbag inflates is formed.
However, when the vehicle undergoes a side collision with a tree or the like and a side door is locally deformed toward the interior of the vehicle, the above-mentioned hinge portion is also deformed locally and its straightness is not maintained at the deformed portion, so that the hinge portion becomes unable to provide its hinge action for the entire upper wall portion of the trim cover. Accordingly, even when the upper wall portion of the trim cover receives inflation force of the airbag, the upper wall portion of the trim cover does not open smoothly, whereby an opening for inflation of the airbag is not properly formed, resulting in occurrence of a problem that the airbag cannot be inflated reliably.